In 2005, Singapore scientist King Bang Lee and colleagues invented a battery powered by urine:

To make the battery, Lee and his colleagues soaked a piece of paper in a solution of copper chloride and sandwiched it between strips of magnesium and copper. This sandwich was then laminated between two sheets of transparent plastic.

When a drop of urine is added to the paper through a slit in the plastic, a chemical reaction takes place that produces electricity, Lee said.

The prototype battery produced about 1.5 volts, the same as a standard AA battery, and runs for about 90 minutes. Researchers said the power, voltage, and lifetime of the battery can be improved by adjusting the geometry and materials used.

Yeah, like would pregnant women's urine be more powerful, or some health nut dude who dosed up on B vitamins? Or would there be a difference in the voltage generated by, say, that strong-smelling deep yellow first-of-the-morning wizz you have, as compared to really weak and watery I've-been-drinking-beer-all-evening-and-my-pee-is-clear kind of urine...?

Yeah, I just read all that...and it's kinda graphic...but you know what I mean, right?